1. Field of the Invention
The present invention relates to an electronic paper display device and a method for manufacturing the same, and more particularly, to an electronic paper display device having excellent display performance and a lower driving voltage and a method for manufacturing the same.
2. Description of the Related Art
Great changes in ways of transmitting and sharing information are required today, in correspondence with a new paradigm that is required in the developing information society. To meet this challenge, the development of flexible electronic paper, which is also called e-paper, has been accelerated and has entered an initial stage of commercial development.
E-paper is much cheaper in terms of production cost than a conventional flat panel display. Since e-paper does not use a backlight to illuminate its pixels, and does not need to be recharged constantly, it can have superior energy efficiency, while running at very low energy. Moreover, e-paper is very clear, has wider viewing angles, and is capable of holding text and images indefinitely without electricity being applied thereto. Due to advantages such as those described above, e-paper may indeed have a variety of applications and have enormous market potential. Applications may include e-books that have a paper-like surface and are capable of displaying digital versions of books, e-paper magazines with moving illustrations, self-updating newspapers, reusable paper displays for mobile phones, disposable TV screens, electronic wallpaper and the like.
Technical approaches for realizing E-paper are roughly classified into 4 methods: a twist ball method for rotating spherical particles, each of which is composed of a upper hemisphere and a lower hemisphere having different colors and opposite polarities, an electrophoresis method for encapsulating a charged color particle mixed with oil within a microcapsule or a microcup and operating the charged particle to respond to the application of an electric field, a QR-LPD (Quick Response-Liquid Power Display) method using charged liquid powders and a cholesteric liquid crystal display method using the selective reflection characteristic of cholesteric crystals.
In the twist ball method, a cell is filled with a transparent medium, and twist balls having opposite charges and having different colors, for example, white and black, are arranged within the transparent medium. When voltage is applied to the twist balls, the twist balls are subjected to the polarity of applied charges, so that the twist balls are rotated according to the direction of voltage such that the charges having opposite polarities are directed toward the front surface thereof, thereby displaying white and black.